Digital intercommunication systems typically work in half-duplex mode and do not include a central control station when all subscribers are fully connected. When carrying out a multi-party conversation in half-duplex mode, at one time, no more than one transmitting subscriber has the right to speak and occupies the physical layer for transmitting voice signals.
In order to ensure that every subscriber has a chance to obtain the right to speak, a configuration is needed for handing over the right-to-speak among the multiple subscribers. Conventional intercommunication systems typically establish certain polling rules for handing over the right to speak, or leave to each subscriber to fight for the right to speak. Such arrangements can be inefficient.
When polling is used, a subscriber who wants to speak may have to wait for a long period of time before it is polled and given the right to speak. As a result, the communication efficiency may be decreased. When the subscribers are allowed to fight for the right to speak, collisions in the physical channel would occur if multiple subscribers want to obtain the right to speak. The back-off associated with such collisions can cause significant delay, and thus wasting precious physical channel resources. Thus, there is a need for improving the handing over of the right to speak among the multiple subscribers in a intercommunication system.